In large bowl of an electric mixer, beat butter and 1/2 cup of the sugar until creamy.
With a fork, blend in 1 cup of the flour until mixture resembles fine crumbs.
Press mixture firmly over bottom of a greased 9 by 13-inch baking pan, forming an even layer.
Bake in a 375Â° oven for 10 minutes; let cool in pan on a rack.
Wash and dry mixer bowl.
Place eggs in bowl and beat until light and lemon-colored; then gradually beat in remaining 1 cup sugar.
Beat in vanilla, remaining 2 tablespoons flour, salt, and baking powder.
Stir in coconut and nuts until thoroughly combined.
Pour coconut mixture over baked crust, spreading evenly.
Return to oven and bake for 20 minutes or until topping is golden; then let cool in pan on a rack for 10 to 15 minutes.
Meanwhile, prepare orange butter frosting, if desired.
Cut partially cooled cookies into bars (about 1 1/2 by 3 or 1 1/2 by 2 inches), but do not remove from pan.
Spread frosting over cookies and let cool completely in pan on rack.
Store covered.